New Information from Radial Velocity Data Sets

Brown, Robert A.

doi:10.1086/421896

Cited by 42 publications

(18 citation statements)

References 4 publications

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“…comm.) is very similar to the ones described in Wright et al (2008) and Brown (2004). The idea is to generate all the possible Keplerian solutions and determine which ones most closely match the data.…”

Section: Hd 7449mentioning

confidence: 93%

The HARPS search for southern extra-solar planets

Dumusque

Lovis

Ségransan

et al. 2011

A&A

126

140

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We present the discovery of four new long-period planets within the HARPS high-precision sample: HD 137388b (M sin i = 0.22. A long-period companion, probably a second planet, is also found orbiting HD 7449. Planets around HD 137388, HD 204941, and HD 7199 have rather low eccentricities (less than 0.4) relative to the 0.82 eccentricity of HD 7449b. All these planets were discovered even though their hosting stars have clear signs of activity. Solar-like magnetic cycles, characterized by long-term activity variations, can be seen for HD 137388, HD 204941 and HD 7199, whereas the measurements of HD 7449 reveal a short-term activity variation, most probably induced by magnetic features on the stellar surface. We confirm that magnetic cycles induce a long-term radial velocity variation and propose a method to reduce considerably the associated noise. The procedure consists of fitting the activity index and applying the same solution to the radial velocities because a linear correlation between the activity index and the radial velocity is found. Tested on HD 137388, HD 204941, and HD 7199, this correction reduces considerably the stellar noise induced by magnetic cycles and allows us to derive precisely the orbital parameters of planetary companions.

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Section: Hd 7449mentioning

confidence: 93%

The HARPS search for southern extra-solar planets

Dumusque

Lovis

Ségransan

et al. 2011

A&A

126

140

View full text Add to dashboard Cite

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“…However, even such poor constraints may help direct the timing and precision of future Doppler work, and they may help interpret data from other detection techniques such as astrometry and direct imaging ( Brown 2004). Motivated by such value, we carried out a two-planet fit to the Keck velocities.…”

Section: Hd 217107mentioning

confidence: 99%

“…Thus, this planet offers an opportunity for direct detection with extreme adaptive optics from ground-based telescopes, space-borne coronagraphic cameras, and interferometers. Velocities obtained during the next few years will help constrain the parameters of this outer planet ( Brown 2004). …”

Section: Hd 217107mentioning

confidence: 99%

Five New Multicomponent Planetary Systems

Vogt

Butler

Marcy

et al. 2005

ApJ

233

274

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We report Doppler measurements for six nearby G-and K-type main-sequence stars that show multiple low-mass companions, at least one of which has planetary mass. One system has three planets, the fourth triple-planet system known around a normal star, and another has an extremely low minimum mass of 18 M È . HD 128311 ( K0 V ) has two planets (one previously known) with minimum masses (M sin i) of 2.18M J and 3.21M J and orbital periods of 1.26 and 2.54 yr, suggesting a possible 2:1 resonance. For HD 108874 (G5 V ), the velocities reveal two planets (one previously known) having minimum masses and periods of (M sin i b ¼ 1:36M J , P b ¼ 1:08 yr) and (M sin i c ¼ 1:02M J , P c ¼ 4:4 yr). HD 50499 (G1 V ) has a planet with P ¼ 6:8 yr and M sin i ¼ 1:7M J , and the velocity residuals exhibit a trend of À4.8 m s À1 yr À1 , indicating a more distant companion with P > 10 yr and minimum mass of 2M J . HD 37124 (G4 IV-V ) has three planets, one having M sin i ¼ 0:61M J and P ¼ 154:5 days, as previously known. We find two plausible triple-planet models that fit the data, both having a second planet near P ¼ 840 days, with the more likely model having its third planet in a 6 yr orbit and the other one in a 29 day orbit. For HD 190360, we confirm the planet having P ¼ 7:9 yr and M sin i ¼ 1:5M J as found by the Geneva team, but we find a distinctly noncircular orbit with e ¼ 0:36 AE 0:03, rendering this not an analog of Jupiter as had been reported. Our velocities also reveal a second planet with P ¼ 17:1 days and M sin i ¼ 18:1 M È . HD 217107 (G8 IV) has a previously known ''hot Jupiter'' with M sin i ¼ 1:4M J and P ¼ 7:13 days, and we confirm its high eccentricity, e ¼ 0:13. The velocity residuals reveal an outer companion in an eccentric orbit, having minimum mass of M sin i > 2M J , eccentricity e $ 0:5, and a period P > 8 yr, implying a semimajor axis a > 4 AU and providing an opportunity for direct detection. We have obtained high-precision photometry of five of the six planetary host stars with three of the automated telescopes at Fairborn Observatory. We can rule out significant brightness variations in phase with the radial velocities in most cases, thus supporting planetary reflex motion as the cause of the velocity variations. Transits are ruled out to very shallow limits for HD 217107 and are also shown to be unlikely for the prospective inner planets of the HD 37124 and HD 108874 systems. HD 128311 is photometrically variable with an amplitude of 0.03 mag and a period of 11.53 days, which is much shorter than the orbital periods of its two planetary companions. This rotation period explains the origin of periodic velocity residuals to the two-planet model of this star. All of the planetary systems here would be further constrained with astrometry by the Space Interferometry Mission.

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“…Brown (2004) describes MC projection for RVM datasets, following the recipe in §15.6 of Press et al (2007).…”

Section: New Techniqes For Estimating F Rv Msinimentioning

confidence: 99%

IMPROVING ESTIMATES OF m sin i BY EXPANDING RV DATA SETS

Brown

2016

ApJ

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We develop new techniques for estimating the fractional uncertainty (F) in the projected planetary mass (msini) resulting from Keplerian fits to radial-velocity (RV) datasets of known Jupiter-class exoplanets. The techniques include (1) estimating the distribution of msini using projection, (2) detecting and mitigating chimeras, a source of systematic error, and (3) estimating the reduction in the uncertainty in msini if hypothetical observations were made in the future. We demonstrate the techniques on a representative set of RV exoplanets, known as the Gang of 27, which are candidates for detection and characterization by a future astrometric direct imaging (ADI) mission. We estimate the improvements (reductions) in F due to additional, hypothetical RV measurements (RVMs) obtained in the future. We encounter and address a source of systematic error, "chimeras," which can appear when multiple types of Keplerian solutions are compatible with a single dataset. We find that for n′ = 10 new, hypothetical RVMs obtained in the last planetary year before 2025, with the same accuracy as the current available RVMs, F is reduced by ~18%. From there, each plus-one increase in 2 log n′ − log q , where q is the factor by which RVM measurement uncertainty is reduced, further reduces F by factor 0.18.

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New Information from Radial Velocity Data Sets

Cited by 42 publications

References 4 publications

The HARPS search for southern extra-solar planets

The HARPS search for southern extra-solar planets

Five New Multicomponent Planetary Systems

IMPROVING ESTIMATES OF m sin i BY EXPANDING RV DATA SETS

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